Research on the influence of large-scale energy storage’s feed-in on the frequency stability of power grid’s receiving-end

In recent years, due to the decrease of energy storage battery cost, the inflection point of commercial operation has been broken through so that energy storage application enters a period of explosive growth. During the China’s "14th fiveyear- plan" period, energy storage cost will be expected to continue to decrease, while the battery cycle life would maintain gradually increase. As a result, it is possible that the large-scale electrochemical energy storage could be applied in power grid. On the account of the excellent power control performance, the large-scale energy storage will play an important role in improving the consumption of renewable energy, ensuring the stable operation of AC/DC hybrid power grid and reducing the investment of peak load regulation. In this paper, the power flow equation and the motor swing equation are combined to analyze the influence of different energy storage distribution on the system frequency transition process. Then, by simulating the electromechanical coupling characteristic of traditional generators, the procedure of energy storage converter responding to grid frequency is researched. In the end, energy storage’ virtual equivalence is proposed to compare with synchronous generator’s frequency regulation capability.